sys = require ("sys")
log = require ("log")
luaboard = require ("luaboard")


--简单判断
if(0)
then
    print("0 为 true")
end

--if else 判断
a = 10;
if( a < 20 )
then
   print("a 小于 20" );
else
    print("a 的值为:", a);
end

--复合判断

if( a < 20 and a >= 10 )
then
   print("a 小于 20" );
else
    print("a 的值为:", a);
end
